JPH04113928U - food containers - Google Patents

Abstract

(57) [Summary] [Purpose] As a container for retort food that is cooked and eaten in a microwave oven, it has excellent heat resistance and insulation properties, and also maintains good gas barrier properties even after retort processing. To provide a food container with excellent preservability. [Structure] A polyester resin foam sheet 1 with a density of 0.9 g/cc or less and a thickness of 0.3 mm or more is used as a base layer, and a resin film layer 2 made of polyamide MXD6 is laminated on the base layer as a container inner layer. A container A is formed from the composite sheet 3.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention mainly applies to foods that are heated and eaten in a microwave oven, especially retort food. The present invention relates to a food container suitable as a food container.

0002

[Problems to be solved by conventional technology and ideas]

Conventionally, food is used to cook stored food in a microwave oven. For product containers, non-foamed polyester resin, polypropylene resin, and similar materials can be used. Many are molded from sheets made of resin mixed with filler. Also From a multilayer sheet in which the resin sheet is used as a base layer and other resin film layers are laminated. There are many things happening.

0003 However, non-foamed polyester resins and polypropylene resins have poor insulation properties. Therefore, when cooking at high temperatures in a microwave oven, do not handle the container with bare hands. It was extremely inconvenient. Especially for polypropylene resins, etc., electronic Items with insufficient heat resistance as the heating temperature with a microwave oven can reach over 150°. Met.

0004 Therefore, heat-resistant polyester resins such as polyethylene terephthalate The foam sheet has excellent insulation properties, so it is suitable for cooking in microwave ovens. Although it is the best material for cooking, it is becoming more and more popular as a food that can be heated in the microwave. Retort food containers have problems with the preservation of the stored food. child This is because there is a problem with the gas barrier properties of the container.

[0005] In other words, although polyester resin foam sheets have excellent heat insulation and heat resistance, Nono, this alone does not have sufficient gas barrier properties, and it has been retort sterilized. However, there are problems with long-term storage stability, and it cannot be said to be suitable. This problem is explained above Not only the polyester resin, but also other resins such as the above-mentioned polypropylene resin. The same can be said about the foam sheet material.

[0006] In order to solve the above problem, the foam sheet was used as a base layer to cover the inner surface of the container. In addition, resin fibres, such as ethylene-vinyl alcohol copolymer and polyvinylidene chloride resin, are used. A method of laminating layers has been proposed, but ethylene-vinyl alcohol copolymer does not have gas barrier properties against oxygen etc. under moisture or in a humid atmosphere. Significantly decreased. In particular, the gas barrier properties deteriorate significantly after retort treatment. If left as is, the long-term shelf life of the retort food will be poor.

[0007] Therefore, the above-mentioned ethylene-vinyl alcohol, which has excellent gas barrier properties, is generally used. On top of the resin film layer such as a copolymer, a resin film with excellent water resistance, e.g. For example, it was necessary to laminate polypropylene film. Nevertheless, the retort The gas barrier property decreases significantly after processing, making it the best container for retort food. I couldn't say that.

[0008] This invention was developed after extensive research to solve the above problems, and has improved its gas barrier properties. Certain superior nylon resins can be used in a moisture-rich atmosphere or after retort treatment. However, the deterioration in gas barrier properties is extremely small, and it also has excellent heat resistance. Focusing on this, we applied this specific resin to the polyester resin foam sheet mentioned above. By laminating the container to form a container, it has excellent heat resistance, heat insulation, and gas barrier properties. In particular, it is retortable and maintains good gas barrier properties even after retorting. A food container with excellent food preservation properties and suitable for use in microwave cooking. It was made into a vessel.

[0009]

[Means to solve the problem]

In other words, the food container of the present invention that solves the above problems has a density of 0.9 g/cc or more. Bottom, a container whose base layer is a polyester resin foam sheet with a thickness of 0.3 mm or more. A resin film layer made of polyamide MXD6 is used as the inner layer of the container. It is characterized by being formed by laminating layers of materials.

0010 The polyester resin that becomes the base material layer is an aromatic dicarboxylic acid and a divalent amine. A high molecular weight chain polyester obtained by reacting alcohol, especially crystalline polyester. Polyethylene terephthalate, which is a polyethylene terephthalate, is preferably used. Crystallinity is related to heat resistance. Therefore, a crystallinity of 20% or more is suitable. This polyester resin is made into a sheet It is used as a foam sheet made by extrusion foam molding.

[0011] The above polyamide MXD6 is a polycondensation product of metaxylylene diamine and adipic acid. It is a type of polyamide, that is, a type of nylon resin, obtained by polymerization. This resin film Under normal conditions, the film is made of polyvinylidene chloride or ethylene-vinyl alcohol. Possesses excellent gas barrier properties comparable to resin films such as copolymers. Especially this Gas barrier properties are significantly improved by biaxially stretching the film. Moreover, The gas barrier properties in an atmosphere containing a lot of water and humidity are It is far superior to resin films such as alcohol copolymers, and is especially suitable for retorts. After treatment, it has several times better oxygen barrier properties, and it also recovers well after retort treatment. It's early.

0012

[Effect]

As mentioned above, the food container of the present invention has a polyester resin foam sheet as the base layer. The inner layer is made of polyamide MXD6, which has excellent gas barrier properties. Since the oil film layer is provided, the container has excellent gas barrier properties, especially when used with water. Retort processing reduces the loss of gas barrier properties in environments with high humidity and humidity. Good gas barrier properties can be maintained even after cooking, and food can be stored well for a long time.

[0013] What's more, the polyester resin foam sheet that is the base material layer makes it safe to use in the microwave. Not only does it retain heat insulation properties that allow it to be handled by hand even after heating, but it also has a foamed base material. The material is made of polyester resin with excellent heat resistance, and before being laminated to this The polyamide MXD6 resin film also has excellent heat resistance, so it is suitable for this type of food. It has sufficient heat resistance as a container, enables retort processing of food, and is There is no risk of deformation even when heated in a microwave.

[0014]

【Example】

In the figures, (A) shows the food container according to the present invention, and (B) shows the food container (A). 2 shows a lid that is sealed by heat-sealing means, adhesive means, etc.

[0015] The food container (A) has a polyester resin foam sheet (1) as a base layer; A resin made of polyamide MXD6 with excellent gas barrier properties is used as the inner layer of the container. The film layer (2) is dry laminated or From the composite sheet (3) laminated by means such as hot melt lamination, vacuum, It is molded into a tray shape using a molding means such as compressed air. (4) is an adhesive layer or The fusing layer is shown.

[0016] In the embodiments shown in FIGS. 1 to 3, the resin film layer made of the above-mentioned polyamide MXD6 (2) alone is laminated on the foam sheet (1) which is the base material layer, but in the embodiment shown in Fig. 4, As shown in FIG. The composite sheet (3) is made by laminating the pyrene resin layer (5). Molding the polypropylene resin layer (5) as an inner layer of the container. You can also do it. Instead of the polypropylene resin layer (5), use another olefin with good oil resistance. In some cases, other resin films such as carbon-based resin films are laminated.

[0017] The polyester resin foam sheet (1) serving as the base layer has a density of 0.9. g/cc or less and a thickness of 0.3 mm or more is used. i.e. foam sheet If the density of (1) is greater than the above, the expected heat insulation properties cannot be obtained. more preferred Or, it has a density of 0.6 or less and g/cc or less. Also, the thickness of the foam sheet (1) If it is smaller than 0.3 mm, the heat insulation properties and shape retention properties will deteriorate, which is not preferable.

[0018] In addition, we also use polyaminated nylon, which is a copolymerized nylon of meta-xylylene diamine and adipic acid. It is preferable that the resin film layer (2) of Mido MXD6 has a thickness of 0.05 mm or less. Delicious. The higher the crystallinity of this resin, the higher the heat resistance and the better the dimensional stability. That's preferable.

[0019] This resin film layer (2) has excellent heat-resistant gas barrier properties, especially moisture resistance. Excellent in maintaining gas barrier properties in humid and humid atmospheres.

[0020] Therefore, the composite sheet (3) containing this resin film layer (2) can be retorted. The gas barrier properties of ethylene-vinyl alcohol copolymer may also decrease due to treatment. It is much smaller than multilayer sheets containing It is possible to maintain the barrier property, and the stored food can be well preserved.

[0021] Moreover, the foam sheet (1) that is the base material is made of polyester resin that has excellent heat resistance. The resin film layer (2) laminated on this material also has excellent heat resistance. Therefore, it has sufficient heat resistance for this type of container and enables high retort processing. Both do not deform even when heated in a microwave oven, and have sufficient shape retention. can be held.

[0022] In addition, the polyester resin foam sheet (1) that is the base material has excellent heat insulation properties. It has excellent insulation properties and can be held in the hand immediately after heating in the microwave. It is also easy to handle after heating.

[0023] In addition, when the polypropylene resin layer (3) is provided on the surface as shown in Figure 4, Due to its steam resistance and water permeability resistance, the gas barrier resin film layer (2) can be well protected, and the gas barrier properties become even more excellent.

[0024]

[Effect of the idea]

As mentioned above, according to the food container of the present invention, a polyester resin foam sheet is used. A resin film layer made of polyamide MXD6 is laminated on this as a base material layer. As a result, excellent gas barrier properties can be maintained even after retort processing, and food In addition to being good for long-term storage, it is also suitable for retort processing and heating in the microwave. It has heat resistance, heat insulation properties that can be held by hand after heating, shape retention, and even resistance. It also has oily properties. Therefore, this invention is suitable for heating and cooking using a microwave oven. It can be suitably used as a container for foods that are eaten by cooking, especially retort foods.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view of the same as above.

FIG. 3 is an enlarged sectional view of a part of the same as above.

FIG. 4 is a partially enlarged sectional view showing another embodiment.

[Explanation of symbols]

(A)...Food container of the present invention (1)...polyester resin foam sheet (2)...Resin film layer of polyamide MXD6 (3)……Composite sheet (5)...Polypropylene resin layer

Claims (1)

[Scope of utility model registration request] [Claim 1] Density 0.9 g/cc or less, thickness 0.3 m
1. A food container having a polyester resin foam sheet of m or more as a base layer, characterized in that a resin film layer made of polyamide MXD6 is laminated on the base layer as an inner layer of the container.